What Does mAh Mean on Alkaline or Rechargeable AA Batteries?

You can't tell how much power is in a new battery, except by looking at its label.

The label on a set of heavy-duty alkaline AA batteries or rechargeable nickel-metal hydride batteries might show a number like 1,000 mAh. But what does that mean exactly?

What does mAh mean on batteries?

The abbreviation mAh stands for milliampere-hours or milliamp-hour, which is how much electricity (in milliamps) that battery can give for one hour. Think of the mAh rating as the AA battery's storage capacity for electricity. An alkaline AA battery labeled with 1,000 mAh can deliver 1,000 milliamps (or one amp) for one hour.

In short, a mAh rating shows the size of your battery's tank, like how a Dodge pickup has a 21-gallon gas tank.

The mAh rating is related to another battery rating common on deep-cycle batteries: the amp-hour or Ah rating on golf cart batteries and other deep cycle batteries. The GC2-ECL-UT golf cart battery has 225 amp-hours — or 225,000 milliamp hours. But, it's too big for your TV remote.

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Does a higher mAh rating mean a battery will last longer?

Not necessarily. How long a battery lasts will depend on how it's used and how often.

For instance, high-powered flashlights, video game controllers and remote-controlled cars need a lot of electricity when they're on. These high-drain devices need batteries with a higher mAh rating.

On the other hand, your TV remote and garage door opener need only a small dose of power every time you push a button. These low-drain devices need less mAh from their batteries.

Milliamp-hours aren't the only thing to watch. Like fruit, batteries can go bad if they sit on the shelf long enough.

The batteries that deliver a lot of power such as 2,500 mAh NiMH rechargeable batteries also tend to have a high self-discharge rate, between 2% and 3% a week. Alkaline batteries also lose power over time, but it takes years. That means an alkaline battery with 1,200 mAh might last far longer in your wall clock than a 2,500 mAh rechargeable battery — because it needs less amperage. Meanwhile, the NiMH battery drains itself waiting for a challenge.

Instead, use them in high-drain devices. You can probably tell that your video game controllers use up alkaline batteries faster than the rechargeable batteries. If you're powering something you use constantly, get the highest mAh rating you can — and you'll find your batteries have longer run times.

Want your batteries to last longer? Match the right battery capacity to the right device.

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